
In a medium-sized saucepan over medium-high heat, add the ½ cup unsalted butter, 2 cups granulated sugar, ½ cup milk, and 4 tablespoons cocoa powder .
Bring to a rolling boil for 1 minute or until the temperature reaches 225°F on an instant-read thermometer. Remove from heat.
Stir in ¾ cup peanut butter , 2 ¾ cups quick oats and 1 tablespoon vanilla, then mix until incorporated.
Line a cookie sheet with parchment paper. Using a medium-sized cookie scoop, scoop the cookies and drop them onto the parchment paper. Let the cookies set and cool to room temperature or refrigerate them before serving.